from decimal import Decimal

class Money(Decimal):
    def __new__(cls, v, units = 'USD'):
        return super(Money,cls).__new__(cls,v)

    def __init__(self,v,units='USD'):
        self.units = units

    def __str__(self):
        return super().__str__() + ' ' + self.units


m = Money('0.11','USD')
print(m,m.units)

